But if you can modify some of these characteristics it may be enough to build an adolescent’s resistance to negative influences, says study author Sylvie Mrug, Ph.D., a child clinical psychologist with the UAB Department of Psychology, who might be the first to study this link.

“There’s a lot of research on temperament and how it relates to behavior and emotional problems and social skills, but no one has looked at temperament together with peer influence,” Mrug says. “Some teens are more likely to follow a bad crowd while other teens may be more resilient, and we found that we can determine who is more at-risk just by virtue of temperament.”

Mrug, an associate professor specializing in developmental psychopathology, and her collaborator studied 704 early adolescents for two years. The five temperament dimensions assessed were activity level, flexibility, mood, sleep rhythmicity and task orientation — how well a child focused on one task. Of those five, low task orientation and low positive mood amplified the negative effects of deviant peers for males and females. Low flexibility was associated with higher vulnerability to negative peer influence only for males.

“Most of the results held across the genders, so there are more similarities than differences between boys and girls,” says Mrug. “Task orientation was most important; boys and girls who get easily distracted or have trouble persevering on a task are more easily influenced by peers. Those are the kids to worry about.”

Mrug hopes these findings will help teens and families. Temperament is biologically based, so it is genetic and fairly stable. You cannot make a child that is very rigid become a flexible child, Mrug says. However, there are intervention programs to increase an adolescent’s self-regulation and task-orientation skills.

“For example, if your child has an attention span of five minutes then they get a reward for doing the task six minutes. Once they are able to do six minutes regularly you increase it to seven or eight minutes,” Mrug said.